Running Miata with (only) intake manifold mounted injectors
 

Why in the world would I want to do this?

Let's just say I don't like swapping injectors to pass emissions and I already have a modified intake manifold with 1 injector per runner which supports my Link Piggyback.

My thought is to install high capacity injectors driven by my soon to arrive MS3 in the normal location and put the stock Miata injectors into the now unused secondary slots in my intake. When inspection time rolls around I'll just swap the Stock ECU in and let it drive the stock injectors. (I plan to add a 2nd wiring harness for the 2nd set of injectors.

They will be farther up stream from the stock location, but can't see much of an issue.

My question: Does anyone have experience with how a Miata would run on the Stock ECU, driving stock injectors mounted in the intake manifold (where FM's Link piggyback had secondary injectors)?

Maybe someone has experience with this based on building their own manifold?

https://www.miataturbo.net/attachmen...ine=1403055640

Hey Rick, where ya from buddy? (Hint, put yer damn location in)
You need to also install a guage to see what your afr's will be for the switch. My guess is it won't be a big deal cause you can tune from the MS3. Ideally, you would want injectors that have a narrower spray pattern. In for the test.
-JB

Seems like a waste of time. I can pull out my ms3 and put my stock injectors and ecu back in the car in less than an hour.

It is slightly harder to swap injectors on an NB style manifold.

Not more than an hour harder. I replaced all my injector o-rings last week in like ~20 minutes. I'm rockin 99 IM.

Thanks Leafy. Yes, the reason for this question is a very difficult to remove upper intake manifold with my current fan / charge pipe / BOV setup. The two front bolts require removing the charge pipe, BOV, both fans and possibly loosening the radiator. It's a tight fit.

So, the question stands, any experience out there?

Worst case I'll just give it a try. I have a wide band O2 sensor installed so my biggest risk is poor air/fuel mix in the manifold causing a lean condition in just one cylindar that I can't detect on the wide band O2. Running without boost I'd guess this is a pretty small risk.

Teach me the ways! How do you deal with the front bolts under the charge pipe? Silicon elbow?

What front bolts under the charge pipe? you just have to remove the upper plenum. When I do it, I remove the charge pipe coupler at the throttle body and unhook the couple vac lines that connect the upper and lower plenums and pull the upper plenum off.

Yep. Loosen t-bolt clamp pop off coupler, disconnect vacuum line or two, remove 6 intake plenum bolts, remove brake booster, and win.... If you have coolant hoses still going to your TB. if you're careful you can just leave them.

I assume the OP means the 'L' shaped bracket that supports the neck of the upper section to the lower part of the intake manifold. 4 M8 bolts, though only 2 really need to be removed.

I was thinking of the wrong pair of bolts. Yes I see how this could work without taking the charge pipe out, etc. Hopefully it's as (relatively) easy as it sounds.

For what it's worth, I'll probably still test running the stock injectors in the intake manifold to close out the question. Might be interesting.

Thanks for the input.